1. Field of the Invention
This invention relates to aircraft landing wheel rotating means.
2. Brief Description of the Prior Art
When an aircraft lands, the tires on the landing wheels receive a large jolt as they are substantially stationary prior to touchdown and then they are suddenly accelerated to approximately the speed of the aircraft in a few seconds after touchdown. This jolt leads to rapid wear of the tires and often results in "flat spots" which unbalance the tires and may lead to blowouts. As the landing speeds of aircraft increase, the problem of tire wear is exacerbated.
Many methods have been proposed to rotate the landing wheels prior to touchdown to reduce the relative speed between the tires and the runway. Examples of these methods are disclosed in U.S. Pat. Nos. 2,313,159 (Gulotta); 2,466,568 (Bean); 2,594,202 (Necchi); 2,665,087 (Clover); 2,777,651 (Gates) and 3,004,738 (Peterson).
Generally these methods rely on the use of an airscoop which directs air under pressure onto a series of turbine blades attached to the landing wheels so that the flow of air over the blades rotates the wheels.
These methods have proved unsatisfactory. The airscoops create considerable unwanted drag, both when the undercarriage is lowered prior to touchdown and when the aircraft takes off, and because they must withstand large air forces, they are heavy, reducing the aircraft payload and increasing the fuel consumption.